The vast majority of industrial cleaning problems are solved with existing technology since these problems have existed for many years and the types of material to be cleaned are typical across different industries. Many industrial cleaners are based on solvent technology where the solvent itself provides the cleaning ability of the product. These cleaners may be “pure” solvents like mineral spirits, Stoddard solvent, 1,1,1-trichloroethane, or others known to those who are skilled in the art. Other cleaners include additives such as emulsifiers or surface-active agents. In addition, other cleaners are water-based and contain varying percentages of solvents dissolved in water or emulsified. Solvent and solvent-based cleaners are regulated by Environmental Protection Agency (EPA) both as volatile organic compounds and as potential water and ground pollutants.
One industry that encounters unique cleaning problems is the hot mix asphalt (HMA) industry. HMA is a mixture of liquid asphalt and aggregate with special additives used to modify the final product to yield a particular set of properties to the finished material and to assist in the mixing and handling properties during manufacturing, transportation, and laying of the surface. HMA as the name implies, is hot, with typical temperatures up to and exceeding 340° F., causing problems with cleaning operations. The liquid asphalt is liquid at the elevated temperatures where it is processed into HMA, but becomes sticky and eventually solid as the temperature falls. During the manufacturing and handling processes, HMA adheres to nearly every surface it contacts. Thus, during the process of paving roads, runways, parking areas, etc., HMA adheres to the equipment involved in manufacturing the asphalt, in transporting the asphalt to the paving site, and in disposing the asphalt on the particular site.
Therefore, the HMA industry is unique because of the nature of the materials encountered and the conditions under which the material is made, transported, and applied, as well as environmental problems encountered during cleaning and reclaiming the cleaner. Similar problems exist in similar industries such as the bitumen industry, the tire-manufacturing industry, the rubber manufacturing industry, and other allied industries.
The largest group of industrial cleaners is based on detergents. The products in this group are water based and contain a surfactant (or a combination of surfactants), and other components. However, these cleaners have proven to be ineffective in removing asphalt or related materials during the cleaning process.
Traditionally, diesel fuel is used as a cleaning agent. However, environmental considerations have resulted in the EPA, the Federal Highway Administration, and many state transportation departments to ban its use. Most other solvent-based cleaners are not effective, present fire and explosion hazards at the elevated temperatures, or are not environmentally acceptable. Emulsions or emulsion forming products containing various hydrocarbons, vegetable based oils and esters (i.e., soy and terpene compounds), or other solvents have been used, but they, like diesel fuel, have a negative environmental impact and/or have potential negative human health effects. Other cleaners have, in the past, indicated that they can remove adhered asphalt from surfaces; however, many of these cleaners are expensive and remove less than 45% of the adhered asphalt.
Thus, there is a need in the industry for a cleaning agent that overcomes at least these disadvantages.